Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.
By: Dr. Jeff Masters , 9:31 AM GMT on November 19, 2005
Dr. Masters was nice enough to write you all a blog entry before he left for vacation. Enjoy what he wrote along with a Gamma Update below.
Message from Dr. Masters
It's probably premature to talk about this, since we may still see more tropical storms this season, but was this year's total of 24 Atlantic tropical storms really a record? It is almost certainly a record for the number of storms since the year 1944. That was the year that the U.S. began flying regular long-range aircraft reconnaissance missions over the Atlantic to detect tropical storms far out over the ocean. According to Dr. Chris Landsea's paper, A Climatology of Intense Atlantic Hurricanes, only a very few short-lived tropical storms that formed far out over the open Atlantic were missed by these aircraft missions or ships plying the shipping lanes between Europe and North America. Beginning 1960, weather satellites gave us full coverage of all the ocean areas, and it is unlikely we missed any tropical storms after then. Looking at the tracks for the 2005 hurricane season, only Tropical Storm Lee may have been short-lived enough to not be detected by aircraft and ships. Similar examinations of the hurricane tracks of storms from the past ten years yields an average of perhaps one storm per year that may have been missed. However, for the period 1851-1910, the Atlantic Hurricane Database Re-analysis Project estimates that the number of missed tropical storms and hurricanes for the 1851-85 era is on the order of 0-6 per year and on the order of 0-4 per year for the period of 1886 to 1910. (The higher detection for the latter period is due to increased ship traffic, larger populations along the coastlines and more meteorological measurements being taken.) There were no years in the the 1851-1885 period with more than 12 tropical storms. But 1887 had 19 tropical storms, so there is a small chance that 1887 tied 2005 with 23 storms if the maximum of four missed storms occurred.
Figure 1. Tracks for all 2005 Atlantic tropical cyclones.
During the 1910-1944 era, there is one other year that might have challenged 2005 for the record number of storms--1933, when 21 tropical storms formed. If we assume that increased ship traffic since the 1886-1910 era resulted in 0-3 tropical storms being missed during 1933, there is a 25% chance that 1933 bested 2005 for the busiest season on record, if a full three storms went undetected. Hurricanes are much harder to hide than tropical storms, though, since hurricanes last longer and typically have long tracks that multiple ships will encounter. Thus, it is likely that this year's tally of 13 hurricanes is unmatched since 1851. There were only 10 hurricanes in 1933, and 11 in 1887.
So in conclusion, the 23 storms and 13 hurricanes observed in 2005 were both very probably records for the post-1850 time period for the Atlantic. There may have been years before 1851 that had greater levels of activity, as the emerging science of paleotempestology is attempting to discover.
Satellite imagery showed an increase in convection north of the storm's center early, but has since decreased once again. The storm center was located at 16.9N 86.2W at 1 a.m. EST with sustained winds at 45 mph. This is 140 miles east-southeast of Belize City.
High pressure north of the storm is expected to weaken, allowing a trough currently over the Plains to sweep the storm on a more northern course. Some strengthening of the system is possible, but wind shear is still high so any further intensification will be limited.
Figure 2. Computer models for Tropical Storm Gamma.
A couple of the (GFS and UKMET) are out to lunch, keeping the storm system in the western Caribbean and dissipating it. The latest run of the GFDL has trended more to the east, keeping the system's center off the Yucatan Peninsula, tracking it over western Cuba and through the Florida Straits. As far as Florida, this model run takes the storm farther south than the run earlier on Friday.
The NHC official forecast trends toward the GFL as the BAM model appears to be too far to the west, taking the storm over the Yucatan Peninsula.
Tropical Storm Warnings have been posted for the coast of Belize where heavy rainfall is also expected. Warnings are also in effect for the eastern coast of the Yucatan Peninsula and the Bay Islands of Honduras.
I will be back later Saturday with another update.
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